211 replies to this topic

[FTodaro]

Have you ever broke a subframe that wasn't hit?
How many hubs have you changed this year?

No subframe ever
Two rear hubs on other peoples cars, none on mine this year.

[Jim Drago]

No subframe ever
Two rear hubs on other peoples cars, none on mine this year.

you answered your own question... 

More than likely rear hub had some wheel to wheel contact.

[38bfast]

All the subframes that I have seen fail are high time / usage components. With the exception of Mark Bennett that I seen fail at the RA runoffs years back that was a low time component. Prior to last year I heard of them faling but only seen personally Marks fail. last year and including this season I have pesonaly seen and replaced 4 failed units. All were 4 plus season units. By the nature af the failure it is obvious it's a fatige issue. The more it's used the more it's prone to failure. I have not seen a two season old unit fail. Not saying it hasn't happened but I have not seen it. According to BSI and Advanced they say they see more of it.

Fracturing rear hub flanges front and rear follow a similar situation. I have personally seen 14 in the past two seasons compared to years back of maybe one a season. I do believe contact has a big part to play in the flange failures. On the cars that replace them at the beginning of each season and whenever contact to that wheel I have not seen a failure. On most of the flange failures we have been able to track them back to having contact. That being said years back we had lots of contact and didn't see the failure rate.

I believe we can all agree that the tire we are on now has more grip than any other tire we have run.

Is the failure rate at a epidemic proportions. I would agree with Jim and say no, But has the rate increesed, I believe yes. I also believe that with preventive maintenance the cars work just just fine with the SM7. But is a hard sell for a car owner to want to replace a part that he can not see a failure in.

[38bfast]

And Jim you seen 3 rear hub flange failures right under your nose at Mid-O this year and there were two more in the paddock that weekend. That's 5 in one weekend at one track.

[TButler]

 

 

However I am definitely open to trying out smaller / harder compound tires. and I would ABSOLUTELY like to see a longer lasting rain tire. 

 

 

 

 

Be careful what you ask for. Pre-Hoosier when SRF ran in Goodyear, we started out with a very good soft rain tire, similar to the Hoosier H2O. The tires were great in the rain and good for multiple sessions *if* the track stayed wet. On a drying track or dry track the tires became toast. Lots of complaints later, Enterprises went to a harder compound rain tire. Basically it was the dry compound with the rain tire grooving. It was like ice skating. Lots more carnage and crash damage and drivers actually parking instead of racing in the rain. Since going to the Hoosier dry tire (same compound as SM7 is my understanding,) SRF now has the Hoosier H2O compound for our rain tire. It is good for multiple sessions in the wet, but goes away on a drying or dry track. Most SRF drivers I know and race with accept the consequences and deal with tire management and prefer a good (aka *real*) rain tire and the confidence it provides vs ice skating on a poor "rain" tire.  

 

Also in the FWIW department, the Hoosier dry for SRF is not fastest as a sticker and generally comes into it's best performance after 3-4+ cycles. Maybe that's just a function of our lighter weight vs SM, but stickers every session is not the answer in SRF.

[Johnny D]

I wasn't ever clear what the poll showed...

 

Did you (driver, SMAC, SCCA) want closer racing (parity) and a higher (TBD) failure rate or

 

Or lower (TBD) failure rate and less parity ??

 

Always mixed and you can't make everyone happy ?

Guys up front will stay up front.

Careful what you ask for.

 

Worth looking into since the contracts coming up, IMO

Is this a action item yet or does someone still need to write a letter?

 

Carry on,

 

J~

[Bench Racer]

Subframe failures grossly exaggerated..

Hub failures real, but slightly exaggerated.  

 

You are mixing two separate topics.. 

The tires are not causing all these problems as IMO most of these problems are exaggerated.  They have real race tires in prod and not having these issues either BTW

 

But these two things are not the same issue IMO

Not picking on Jim as a person, only picking on his comments. Others in this thread have made similar comments. Tinny bullshit flag.

 

Before talking hub and frame failures, I totally agree with the TButler post on H2O tires and Brians post on WKA Karting tires, except I believe in the early 1990's WKA Senior Sportsman ran on YBX otherwise I could not have w2w raced with them because I sure as hell didn't buy stickies for a couple WKA races a year. My normal home track was Dousman/Badger Kart Club. Also did the WKA Grand Nations in 92 or 93.

 

My association with 2 cars raced HARD for several years, 8ish weekends per year each. One a 1990 Miata procured in Atlanta in 2009 which had seen abuse on the race track, and has been converted from SM to ITA to STL and constantly in ITA and STL using A7 tires. One 1990 Miata F production car procured from the south east in 2010 or 2011 always using race slicks. Each of these cars are 8 plus years old. Raced in the South East, CenDiv and Runoffs wherever.

A. NO CRACKED SUB-FRAMES, NO SPECIAL WELD IN BRACES.

B. NO BROKEN CRACKED/FRACTURED DIFFERENTIAL HOUSINGS.

C. HUBS, FROM LESSONS LEARNED, CONSTSNT PREVENTIVE MAINTENANCE SAME AS CHANGING OIL.

 

What's with points A. and B., simple, NO CAR TO CAR contact and NO BUMP DRAFTING.

What's with point C., simple WHEEL OFFSET AND STICKY TIRES.

 

How to greatly minimize sub-frame failures, differentia housing failures and hub failures.

 

Rules:

Less wheel offset.

Less sticky/harder/narrower/wider/whatever dry tires.

5 tires per double race weekend. 

Follow the existing SCCA rule on car to car contact.

 

The above are valid factual points. I'll argue with anyone who argues with facts on the points above.

[Danny Steyn]

 

Worth looking into since the contracts coming up, IMO

Is this a action item yet or does someone still need to write a letter?

 

 

 

Contract comes up for renewal end of the 2018 season IIRC

 

Letters are in the system for both rain tire and a harder wearing/more HC tire, but feel free to submit letters for whatever you believe the right tire is

[Martinracing98]

 

Be careful what you ask for. Pre-Hoosier when SRF ran in Goodyear, we started out with a very good soft rain tire, similar to the Hoosier H2O. The tires were great in the rain and good for multiple sessions *if* the track stayed wet. On a drying track or dry track the tires became toast. Lots of complaints later, Enterprises went to a harder compound rain tire. Basically it was the dry compound with the rain tire grooving. It was like ice skating. Lots more carnage and crash damage and drivers actually parking instead of racing in the rain. Since going to the Hoosier dry tire (same compound as SM7 is my understanding,) SRF now has the Hoosier H2O compound for our rain tire. It is good for multiple sessions in the wet, but goes away on a drying or dry track. Most SRF drivers I know and race with accept the consequences and deal with tire management and prefer a good (aka *real*) rain tire and the confidence it provides vs ice skating on a poor "rain" tire.  

 

Also in the FWIW department, the Hoosier dry for SRF is not fastest as a sticker and generally comes into it's best performance after 3-4+ cycles. Maybe that's just a function of our lighter weight vs SM, but stickers every session is not the answer in SRF.

 

 

I agree completely. Unfortunately rain tires wear out quickly on a drying track. I am not sure there is much good to do about it. The previous rain tires on SRF were not the answer. The new rain tires are much better, and the dry tires I think are probably a benchmark for getting it right. I am considering moving from Spec Racer Ford Gen 3. Moving away from genuine 13 session tires is one of biggest items on the con side.

[Danny Steyn]

 I am considering moving from Spec Racer Ford Gen 3. Moving away from genuine 13 session tires is one of biggest items on the con side.

 

 

Not sure I understand Martinracing8, - Are you considering moving FROM SRF3 to possibly SM?

 

Reason I ask is I have been told that several of the front runners are able to race competitively with 10- 15 HC on the current SRF3 Hoosier tire (same compound as SM7). Can you confirm this hearsay?

 

Obviously the SRF3 is much lighter car than us, but also carries higher cornering speeds, more braking deceleration and faster acceleration. 

[Martinracing98]

Not sure I understand Martinracing8, - Are you considering moving FROM SRF3 to possibly SM?

 

Reason I ask is I have been told that several of the front runners are able to race competitively with 10- 15 HC on the current SRF3 Hoosier tire (same compound as SM7). Can you confirm this hearsay?

 

Obviously the SRF3 is much lighter car than us, but also carries higher cornering speeds, more braking deceleration and faster acceleration. 

Yes, I am considering switching. I really enjoy the driving the SRF3 cars. But also like tinkering now that my job does not have me on the road 50% of the time. My transmission is getting new gears right now. I wish I could do it both for the money savings and satisfaction.

 

To your question though. I am a mid-pack runner and I know at 13 cycles I am running the same place in the pack as I was running at the beginning of the season when they were new. This is all at well supported races. I saw one guy got on the podium at COTA with leftovers from the runoffs. Others are running tires basically to cords. They really are lasting. I do not know if Hoosier, or someone else, can come up with a tire that successful for SM, but it is a worthwhile goal. 

[38bfast]

And Jim you seen 3 rear hub flange failures right under your nose at Mid-O this year and there were two more in the paddock that weekend. That's 5 in one weekend at one track.

https://m.youtube.co...h?v=3m5qxZm_JqM

[Bench Racer]

38bfast, home run on the Senator Collins video. Sorry Mike.  John D. could you do a remake of the video with two Senator Collins?

 

Per Senator Collins, "sub-frame failures grossly exaggerated"..

 

Per me, let's say all sub frame failures which fail were where the new Mazda bracket welds in place to strengthen the lower control arm sub-frame attachment location. 

 

Per 38bfast, "All the sub-frames that I have seen fail are high time / usage components".

 

Per me, let's say all sub frame failures which fail were where  the new Mazda bracket welds in place to strengthen the lower control arm sub-frame attachment location.

 

No one cares to argue my sub-frame point in post #147. Those sub-frames not failing are not "exaggerated" and the are "high time" way beyond any of the frames Senator Collins and 38bfast are referencing and neither of the two cars referenced in post #147 has had/viewed a lower control arm sub-frame attachment location crack or fail.

 

How come ^, are people not seeing the forest through the trees? Or don't people care to see the forest because harder/higher heat cycle tires may be the result and there would be less pointy end cars. Oh, almost forgot, likely SM racing would be more economical.

 

Beyond all that above, now that the Mazda bracket strengthens the lower control arm sub-frame attachment location, where is the next weak link WHICH WILL FAIL?

[Jim Drago]

38bfast, home run on the Senator Collins video. Sorry Mike.  John D. could you do a remake of the video with two Senator Collins?

 

Per Senator Collins, "sub-frame failures grossly exaggerated"..

 

Per me, let's say all sub frame failures which fail were where the new Mazda bracket welds in place to strengthen the lower control arm sub-frame attachment location. 

 

Per 38bfast, "All the sub-frames that I have seen fail are high time / usage components".

 

Per me, let's say all sub frame failures which fail were where  the new Mazda bracket welds in place to strengthen the lower control arm sub-frame attachment location.

 

No one cares to argue my sub-frame point in post #147. Those sub-frames not failing are not "exaggerated" and the are "high time" way beyond any of the frames Senator Collins and 38bfast are referencing and neither of the two cars referenced in post #147 has had/viewed a lower control arm sub-frame attachment location crack or fail.

 

How come ^, are people not seeing the forest through the trees? Or don't people care to see the forest because harder/higher heat cycle tires may be the result and there would be less pointy end cars. Oh, almost forgot, likely SM racing would be more economical.

 

Beyond all that above, now that the Mazda bracket strengthens the lower control arm sub-frame attachment location, where is the next weak link WHICH WILL FAIL?

I would love to comment.. Unfortunately I have no idea what point you are even trying to make

[SaulSpeedwell]

All the subframes that I have seen fail are high time / usage components. With the exception of Mark Bennett that I seen fail at the RA runoffs years back that was a low time component. Prior to last year I heard of them faling but only seen personally Marks fail. last year and including this season I have pesonaly seen and replaced 4 failed units. All were 4 plus season units. By the nature af the failure it is obvious it's a fatige issue. The more it's used the more it's prone to failure. I have not seen a two season old unit fail. Not saying it hasn't happened but I have not seen it. According to BSI and Advanced they say they see more of it.

 

 

Actually, I failed the lower balljoint at the Runoffs, never had a subframe failure myself.  From the sidelines, it sure seems like various failures are on the rise. 

 

There is zero mathematical doubt that the suspension and wheel ends are seeing MULTIPLES of the loads of a stock car, and there is zero mathematical doubt that more offset, taller tires, heavier tires, and stickier tires, all increase those loads.  But running into things, cars, walls, sandtraps, has still got to be the worst loads we can experience?

[Bench Racer]

I would love to comment.. Unfortunately I have no idea what point you are even trying to make

Why do the diff. housing break and sub-frames break on some Spec Miata cars and not break on the two specific 1990 STL and H production cars identified in post # 147 and 153 which have minimal car to car contact and have not been bump drafted. Yes indeed, run any of the spec line cars into a wall and the diff. and sub-frame are bound to break

 

Not trying to beat what some consider a dead horse, curious as to why the STL and H prod cars don't break. There may be info in the details which would help with considering a future tire choice. 

[Michael Novak]

Why do the diff. housing break and sub-frames break on some Spec Miata cars and not break on the two specific 1990 STL and H production cars identified in post # 147 and 153 which have minimal car to car contact and have not been bump drafted. Yes indeed, run any of the spec line cars into a wall and the diff. and sub-frame are bound to break

 

Not trying to beat what some consider a dead horse, curious as to why the STL and H prod cars don't break. There may be info in the details which would help with considering a future tire choice. 

The diff covers break because of bump drafting and hits/crashes---simple.... Bump drafting is part of Spec Miata and I don't know of anyone who doesn't want it ---I am sure there are though.......   I think the sub frames are the wheel to wheel contact that happens and the age of the parts the rest of the time.  

 

The subframes will break---just a matter of time in any class. Spec Miatas as a whole I believe get raced more often and harder than most any other class. I think they also go off track more---hit more curbing etc etc.. than most classes. Spec Miata will find the weakest point of a Miata faster then any other Miata able to be run in class.

[38bfast]

One contributing issue we have over other classes is that we are hard on the bump stops. Thus no suspention compliance to take up the hard hits of curbing, off track, or big bumps in the track.

[LarryKing]

 

Bump drafting is part of Spec Miata and I don't know of anyone who doesn't want it

 

I could live without bump drafting. (Too many drivers don't know how)

[Jim Drago]

Why do the diff. housing break and sub-frames break on some Spec Miata cars and not break on the two specific 1990 STL and H production cars identified in post # 147 and 153 which have minimal car to car contact and have not been bump drafted. Yes indeed, run any of the spec line cars into a wall and the diff. and sub-frame are bound to break

 

Not trying to beat what some consider a dead horse, curious as to why the STL and H prod cars don't break. There may be info in the details which would help with considering a future tire choice. 

Mike Novak hit on it earlier.. 

 

In Production and other faster Miata classes where they run stickier tires and put MORE load on the same parts they don't fail these parts at near the supposed rate we do. Our rate is also exaggerated...  How many times do people go to the track and not fail these parts over a weekend and come back and post about it? Sm cars are raced harder than most other miatas in other classes,  as in wheel to wheel contact, jumping curbs etc.  All driven by competition.    So would a harder less sticky tire solve this issue, NO way. Would it help, common sense would say less grip has to help. I don't think we know these "problems" are even coming from the extra grip, if so how much is related to the extra grip?  My opinion is that is you race a car 10 weekends a year,  for 2-5 years in the manner we race these cars.. You SHOULD expect to change a few parts.  Who would run a car for 4-5 years and not inspect for cracks to a subframe?  I'm fine with the gussets as it makes the masses happy and it is inexpensive. My concern is with the first sign of any little failure,  we have engineers ready to design a new part and submit it for approval. Slowly transitioning our class closer to prod. Bad idea! 

 

again, in a non related topic IMO, I would support a tire ( harder or softer) that lasts 7+ raceable sessions.